Nonrecrystallized refractory material



Patented June 12, 1923.

UNITED STATES 1,458,913 PATENT OFFICE.

WILLIAM A. FARISH, OF BUFFALO, NEW YORK, ASSIGNOR TO BUFFALO REFRACTORYCORPORATION, OF BUFFALO, NEW YORK, A CORPORATION OF NEW YORK.

NONRECRYSTALLIZED REFRACTORY MATERIAL.

No Drawing.

T 0 all whom it may concern:

Be it known that I, IVILLIAM A. FAmsH, a citizen of the United States ofAmerica, and a resident of the city of Buflalo, county of Erie, andState of New York, have invented certain new and. useful Improvements inN onrecrystallized Refractory Materials, of which the following is afull, clear, and exact description.

The general object of my invention has been to provide a refractorymaterial which shall be of such a nature as to resist chemical actionand which shall greatly increase the life of articles which are madetherefrom.

Another object has been to provide a material which shall giveelasticity to the articles which are made therefrom, thereby preventingcracking and disintegrating, as well as giving, to the articles,resistance against oxidizing and corroding, thus making it possible toproduce articles which are very durable.

Furthermore my material is of such a nature that the articles madetherefrom shall be unaffected by water or moisture and, therefore, maybe used at any desired time without the necessity of giving to them apreliminary curing or drying.

Moreover, it has been an object to provide a refractory material theconstituent ingredients of which may be permanently bound together in arefractory article without the necessity of raising the temperature ofthe material to the point of recrystallization. The ingredients of mymaterial are inexpensive and heat resisting articles may be economicallymanufactured therefrom.

It is obvious that my material may be used for any heat resistingarticles; but, for example, in this specification, I will describe thematerial as applied to the construction of a crucible.

It is well known to those skilled in the art, that the present daycrucibles known to the trade as graphite crucibles are made either fromplumbago or graphite and preferably German clay, together with a slightadmixture of silica, usually sand. Due to the action of the furnacefires on the outside of such crucibles, and also from the af-.

fects of fluxes on the inside thereof, these graphite crucibles oxidizeand disintegrate quite rapidly. Together with the above mentioneddisadvantages, the repeated'heatla pin Application filed October 9,1920. Serial No. 415,871.

ing and cooling to which such crucibles are subjected in ordinary use,causes large sheets to flake ofi' (termed seal-ping) and also causesthem to crumble, which results in a crucible of comparatively shortlife.

My material is preferably composed'of the following elements in theproportions named:

Parts. Silicon carbide, substantially r 44.5 Crystalline graphite,substantially 20 Sand, substantially 11 Tar, substantially 20 Borax,substantially 4.5

and that it is far below the temperature necessary to recrystallize theingredients of the refractory material, thus resulting in a great savingof heat necessary to bake the articles made from my material.

that this temperature is comparatively low I have discovered, fromrepeated experiments, that if heat resisting articles are to be durable,it is necessary that a portionof natural crystalline graphite beemployed. This crystalline graphite, lies in thin laminae or layersoverlapping one another which enables the article to withstand suddenchanges in temperature without cracking, due to a certain amount offlexibility given to the whole body of the article by the overlayers ofgraphite.

i e I have set forth tar as the carbonizing binder in my material, it isobvious that any other suitable carbonizing binder such as pitch ormolasses may be used if desired. Furthermore, while I have set forth theuse of sand and borax, either one of these may be used singly or anyother fusion mixture which will protect the carbonizing binder' fromoxidation may be used if desired. I have found, however, that the use ofthe sand and borax produces an ideal fusion mixture, since the boraxgives quicknessof action to the mixture and the sand forms a body andgives a more permanent flux than the borax would give if used alone. Theuse of the fusion mixture not only protects the carbonizing binder butalso forms a protecting coating around the graphite.

While I have set forth certain proportions of the different ingredients,it is obvious that they may be varied somewhat without departing fromthe spirit of my invention or the scope of the appended claims and I donot wish, therefore, to be limited to the exact proportions ofingredients herein set forth.

While I have used the term crystallized in this application as appliedto graphite, it is to be understood that this term also includes flakegraphite which is the equivalent of crystalline graphite.

Having thus described my invention, What I claim is:

1. A non-crystallized refractory material for heat resisting articlescomprising silicon carbide, crystalline graphite, a carbonizing binder,and sand.

2. A non-crystallized refractory material for heat resisting articlescomprising silicon carbide, crystalline graphite, tar, and sand.

3. A non-recrystallized refractory material for heat resisting articles,comprising silicon carbide, crystalline graphite, a carbonizing binder,borax and sand.

4. A non-recrystallized refractory material for heat resisting articles,comprising silicon carbide, crystalline graphite, tar,

borax and sand.

5. A refractory material for heat resisting articles comprising,substantially 44.5 parts of silicon carbide. substantially 20 parts ofcrystalline graphite, substantially 20 parts of tar, and substantially15.5 parts of a fusion mixture.

6. A refractory material for heat resisting articles comprising,substantially 44.5 parts of silicon carbide, substantially 20 parts ofcrystalline graphite, substantially 20 parts of tar, and substantially15.5 parts of a mixture of borax and sand.

7. A refractory material for heat resisting articles comprising,substantially 44.5 parts of silicon carbide, substantially 20 parts ofcrystalline graphite, substantially 20 parts of tar, substantially 4.5parts of borax, and substantially 11 parts of sand.

In testimony whereof, I have hereunto signed my name.

WILLIAM A. FARISH.

